He complained for months about incessant dog barking coming from homes all around him. He even put up fliers on doors throughout his Phoenix townhome complex advising people of pet ordinances and fines.

This weekend, police say, the 56-year-old went on a rampage, methodically killing four members of a family who lived next door, along with their two dogs. He then walked across a courtyard and tried to kill more neighbors with dogs before he went home and killed himself.

One of the victims, Renee Moore, "told me all the time the man was crazy," said her mother-in-law, Jacque Alderman, 70. "He just couldn't stand the dogs."

Also killed in the Saturday shooting were Moore's father, Bruce Moore, 66; her husband, Michael Moore, 42, who used his wife's last name; and her son, Shannon Moore, 17.

Libni Deleon, 26, said that just a few months ago he returned home from work to find Guzzo standing by his back gate where his two dogs were on the patio barking.